CVE-2020-5143
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSonicOS SSLVPN login page allows a remote unauthenticated attacker to perform firewall management administrator username enumeration based on the server responses. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe SonicOS SSLVPN login page allows remote unauthenticated attackers to enumerate valid firewall management administrator usernames by observing differences in server responses. This information disclosure enables attackers to gather valid usernames for subsequent brute-force or credential stuffing attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 5.9.1.13>= 6.0.0.0, <= 6.0.5.3>= 6.5.0.0, <= 6.5.1.11>= 6.5.4.0, <= 6.5.4.7= 7.0.0.0<= 6.5.4.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify installed SonicOS versionLog into the Sonicwall management interface and navigate to System > Status to view the firmware version, or use the command line and run 'show version' via SSH/consoleAffected if The version falls within any of these ranges: <= 5.9.1.13; >= 6.0.0.0 and <= 6.0.5.3; >= 6.5.0.0 and <= 6.5.1.11; >= 6.5.4.0 and <= 6.5.4.7; = 7.0.0.0 (for SonicOS) or <= 6.5.4.4 (for SonicOSv)
-
Confirm SSLVPN is enabledLog into the Sonicwall management interface and navigate to VPN > SSL-VPN Settings to verify the SSLVPN service is enabled, or check via command line with 'show ssl-vpn config'Affected if SSLVPN is enabled and accessible from the network
-
Check SSLVPN login endpoint exposureAttempt to access the SSLVPN login page externally (for example, via https://<firewall-ip>/ssl-vpn/login.html) from an untrusted network to confirm the endpoint is reachableAffected if The SSLVPN login page is reachable from untrusted networks without authentication
-
Test for username enumeration response differencesSend two HTTP POST requests to the SSLVPN login endpoint with different usernames (one known-valid, one random) and compare the server response codes, response times, or error messagesAffected if The responses differ between valid and invalid usernames in a way that reveals whether an account exists
You are affected if your SonicOS version is in the affected list AND the SSLVPN login page is accessible, allowing an attacker to distinguish valid from invalid usernames via differing server responses.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor patches for the affected SonicOS versions. If patches are unavailable, implement network-level access controls or rate limiting on the SSLVPN login endpoint to reduce enumeration attempts.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-5143 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-5143 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data